Today is tomorrow’s yesterday: Children’s acquisition of deictic time words

Abstract

Deictic time words like "yesterday" and "tomorrow" pose a challenge to children not only because they are abstract, and label periods in time, but also because their denotations vary according to the time at which they are uttered: Monday's "tomorrow" is different than Thursday's. Although children produce these words as early as age 2 or 3, they do not use them in adult-like ways for several subsequent years. Here, we explored whether children have partial but systematic meanings for these words during the long delay before adult-like usage. We asked 3- to 8-year-olds to represent these words on a bidirectional, left-to-right timeline that extended from the past (infancy) to the future (adulthood). This method allowed us to independently probe knowledge of these words' deictic status (e.g., "yesterday" is in the past), relative ordering (e.g., "last week" was before "yesterday"), and remoteness from the present (e.g., "last week" was about 7 times longer ago than "yesterday"). We found that adult-like knowledge of deictic status and order emerge in synchrony, between ages 4 and 6, but that knowledge of remoteness emerges later, after age 7. Our findings suggest that children's early use of deictic time words is not random, but instead reflects the gradual construction of a structured lexical domain.

The mental timeline is gradually constructed in childhood

“…Although past studies have shown that preschoolers can use explicit timelines and other physical artifacts to coarsely differentiate the times of events, this typically required adult demonstrations and extensive explanation (Busby Grant & Suddendorf, 2009;Friedman, 2000Friedman, , 2002Friedman & Kemp, 1998;Friedman, 2000Friedman, , 2002Tillman, Marghetis et al, 2017). Spatial priming was strikingly effective, given how minimal the intervention was.…”

“…To our knowledge, although several studies have asked how children map time onto external spatial artifacts (e.g., Berteletti, Lucangeli, & Zorzi, 2012;Busby Grant & Suddendorf, 2009;Friedman, 2000Friedman, , 2002Friedman & Kemp, 1998;Hudson & Mayhew, 2011;Tillman, Marghetis, Barner, & Srinivasan, 2017), and others have examined the direction of children's counting (e.g., Göbel, McCrink, Fischer, & Shaki, 2018;Shaki, Fischer, & Göbel, 2012), only two previous studies have tested whether children produce LR representations of time in the absence of training or experimentally imposed artifacts that force the use of a line. One study (Dobel, Diesendruck, & Bölte, 2007) showed that while adults and literate children tended to represent the agent, object, and recipient in a verbally described event congruently with their reading/ writing direction, preschoolers did not show this bias.…”

Time Points: A Gestural Study of the Development of Space–Time Mappings

“…Tillman, Marghetis, Barner, and Srinivasan (2017) have demonstrated that while 6-year-olds rarely make errors about the deictic status of the sort of time words used in the current study, knowledge about the relative remoteness of temporal locations improves considerably between 6 and 8 years. Disentangling the precise effect that age has on marking magnitude is difficult because there were age group differences in the relative proportion of lateral to sagittal gestures, with magnitude being more likely to be marked in the former than the latter axis.…”

“…If we limit our analysis to just instances where participants produced two spatial gestures in the lateral axis, we see a difference between the adults and the three younger age groups, with adults more likely to mark magnitude differences in their gestures than each of the children groups. Tillman, Marghetis, Barner, and Srinivasan (2017) have demonstrated that while 6-year-olds rarely make errors about the deictic status of the sort of time words used in the current study, knowledge about the relative remoteness of temporal locations improves considerably between 6 and 8 years. This suggests that the youngest children may have marked magnitude less than adults because they had a less firm grasp on the relative magnitudes of the distances.…”

On the human uniqueness of the temporal reasoning system

“…As H&M point out, simply being able to say temporal words should not be taken as evidence that children fully understand them, or that they have TR capacities that would allow this. Relevant to this, beyond the early studies of "before" and "after," more recent research has examined children's acquisition of additional classes of time words Busby-Grant & Suddendorf 2011;Shatz et al 2010;Tillman & Barner 2015;Tillman et al 2017;Zhang & Hudson 2018a). These other lexical categories are linked to key facets of the adult TR system.…”